The present invention pertains to a rack for accommodating electronic plug-in boards with a board cage on the front side, a board cage on the rear side, at least one vertical backplane that is arranged between the board cage on the front side and the board cage on the rear side, an installation space that is provided underneath the board cage on the front side and into which at least one fan module can be horizontally inserted from the front side, and a power supply module with an electronics unit that supplies the backplane with power.
Such a rack is used, for example, in modular computer systems for the telecommunication industry. In this case, the board cage on the rear side is significantly shorter than the board cage on the front side. The individual plug-in boards are plugged into the backplane arranged between the two board cages. The rack encloses the board cage on the front side and the board cage on the rear side, as well as the installation space for fans located underneath.
Due to the different sizes of the board cages, the board cage on the rear side can only accommodate significantly shorter plug-in boards than the board cage on the front side. Accordingly, the power demand of the smaller plug-in boards is also lower than the power demand of the larger plug-in boards.
The power supply of the backplanes and the plug-in boards connected thereto is realized with a special power supply module. This power supply module is connected to the main backplane and usually located underneath the board cage on the rear side. It frequently occupies the entire space underneath the board cage on the rear side or at least a large portion of this space.
Electric fans are arranged underneath or above the board cage on the front side in order to cool the plug-in boards during the operation. These fans generate an air current that flows around the plug-in boards on the front side. Openings are frequently provided in the backplane in order to also cool the plug-in boards in the board cage on the rear side. The cooling air flows through these openings and into the rear board cage past the power supply module. The air current that reaches the plug-in boards in the board cage on the rear side therefore is significantly weaker than in the cage on the front side.
New standards on modular computer systems such as, for example, AdvancedTCA Extensions define a modular construction system with a rack, the board cage of which on the rear side has the same size as its board cage on the front side. The plug-in boards that were only installed in the board cage on the front side until now should also be used with identical size in the board cage on the rear side. This increases the power demand of the plug-in boards on the rear side as high as 500 Watt. The cooling demand of the rear plug-in boards increases accordingly. The required cooling of the board cage on the rear side can no longer be ensured with the existing cooling concept.